Conventional movies are formed from a time-series of scenes. They contain no scenes which proceed simultaneously. Hence, the audience sees only one scene at a time on the screen. The audience cannot enjoy seeing another scene which can proceed along with the scene they are actually seeing. For example, the audience cannot see a scene of the cockpit of a space shuttle and a scene of the ground control center at the same time, though these scenes are proceeding simultaneously. This is because these scenes have been connected together forming a sequential time series of scenes which is generally known as a movie film. Another example may be an opera movie. Some of the audience may wish to see only the scene of the entire orchestra for some time, some others may want to watch the zoom-up face of a leading opera singer-player, and still some others may like to look into the conductor's zoom-up face. In other words, people in the movie theater may wish to, but cannot, see different scenes at different timing. With television broadcasting, it is possible to present two scenes of the same program at the same time on a multi-screen. For instance, a moving picture of an object, photographed at a long distance, and a moving zoom-up picture of the same object can be transmitted on two channels, respectively. Therefore, the TV watcher can select whichever picture he or she wants to see on the TV screen at any timing he or she wants.
However, the program data recorded on a recording medium is nothing but a time-series of scenes, and the user cannot see any other scene than the very scene being reproduced from the medium. In other words, he or she is unable to select one of the simultaneously proceeding scenes. Although movie film editors can combine two simultaneously proceeding scenes, forming a times series of scenes, the user can have but a limited freedom of selecting scenes.
With television broadcasting technology it is possible to transmits two or more simultaneously proceeding scenes through a plurality of channels. The program data recorded on a recording medium represents a time series of scenes, and the user has no freedom of selecting any one of simultaneously proceeding scenes.